Piston rings are well known. They are usually received within an annular groove disposed about an outer periphery of a piston. In turn, the piston is reciprocable within a cylinder. A piston compresses fluids such as gases within a cylinder. In the case of an internal combustion engine, these fluids are ignited, and expand, forcing the piston away from the point of ignition. Conventional piston rings are not in total circumferential contact with the walls of a cylinder. Instead, there is an open-end clearance which results in the undesirable escape of fluids from the cylinder. This lowers efficiency and in some cases, as with internal combustion engines, adversely impacts the environment. Further, fluids such as gases may also bypass the portion of the ring received in the annular groove of the piston. Axially acting loads applied to the ring results in damaging wear to the ring and sides of the piston groove. Additional fluid may then bypass the ring.
Piston rings which sealingly engage a cylinder wall are known. In one such piston ring, several layers are riveted together to form the seal. Such sealing members, however, have been subject to a number of disadvantages. First, such piston rings are typically expensive to produce because of their complicated structures and constructions. Additionally, many such sealing members are difficult to install, increasing the time required for assembly. Even when correctly installed, such sealing members typically result in a high level of unwanted frictional interaction between the piston ring and the cylinder wall. This frictional interaction results in increased wear to both the sealing member and the cylinder wall with a corresponding reduced efficiency of the piston in operation.